1 files changed, 46 insertions, 0 deletions
diff --git a/V3/Screens/FpsCounter.cs b/V3/Screens/FpsCounter.cs
new file mode 100644
index 0000000..5c3ac0c
--- /dev/null
+++ b/V3/Screens/FpsCounter.cs
@@ -0,0 +1,46 @@
+using System;
+using Microsoft.Xna.Framework;
+
+namespace V3.Screens
+{
+    /// <summary>
+    /// Counts the frames per second based on the elapsed time and the number
+    /// of frames that have been drawn.  Call Update in each Update, and
+    /// AddFrame in each Draw.
+    /// </summary>
+    public sealed class FpsCounter
+    {
+        /// <summary>
+        /// The current frames per second.
+        /// </summary>
+        public int Fps { get; private set; }
+
+        private int mFrameCount;
+        private TimeSpan mTimeSpan = TimeSpan.Zero;
+
+        /// <summary>
+        /// Updates the elapsed time and -- once every second -- the fps value.
+        /// </summary>
+        /// <param name="gameTime">the elapsed game time</param>
+        public void Update(GameTime gameTime)
+        {
+            mTimeSpan += gameTime.ElapsedGameTime;
+
+            if (mTimeSpan > TimeSpan.FromSeconds(1))
+            {
+                mTimeSpan -= TimeSpan.FromSeconds(1);
+                Fps = mFrameCount;
+                mFrameCount = 0;
+            }
+        }
+
+        /// <summary>
+        /// Registers that a frame has been drawn. Should be called once for
+        /// every Draw.
+        /// </summary>
+        public void AddFrame()
+        {
+            mFrameCount++;
+        }
+    }
+}